How to Calculate Workday Length With Lunch Breaks
Knowing exactly how long your workday is – and how much of it is paid – helps you verify your paycheck and plan your schedule. This step-by-step guide shows you how to calculate your workday length with examples.
The Basic Formula
Calculating your workday length involves a simple formula:
Paid Work Hours = (End Time – Start Time) – Unpaid Break Time
Let's break this down step by step with practical examples.
Step-by-Step Calculation Process
Step 1: Calculate Total Time at Work
First, determine how long you're at your workplace from arrival to departure. Subtract your start time from your end time.
Example: Start at 9:00 AM, end at 5:30 PM
5:30 PM – 9:00 AM = 8 hours 30 minutes total time at work
Step 2: Identify Your Breaks
List all your breaks and categorize them:
- Paid breaks: Short rest breaks (5-20 min) – don't deduct these
- Unpaid breaks: Meal breaks (30+ min) – deduct these from your hours
Step 3: Subtract Unpaid Break Time
Only subtract unpaid breaks from your total time at work.
Example: 8h 30m total – 1h unpaid lunch = 7h 30m paid
Step 4: Convert to Decimal (If Needed)
Many payroll systems use decimal hours. Convert minutes to decimals by dividing by 60.
Common conversions:
15 minutes = 0.25 hours
30 minutes = 0.5 hours
45 minutes = 0.75 hours
7h 30m = 7.5 decimal hours
Practical Examples
Example 1: Normal Office Day with 30-Minute Lunch
Scenario
- Start: 9:00 AM
- End: 5:00 PM
- Lunch: 30 minutes unpaid
- Coffee break: 15 minutes paid
Calculation
- 1. Total time: 5:00 PM – 9:00 AM = 8 hours
- 2. Unpaid breaks: 30 minutes
- 3. Paid work hours: 8h – 30m = 7h 30m (7.5 hours)
Note: The 15-minute paid coffee break doesn't reduce your hours.
Example 2: 12-Hour Shift with 1-Hour Lunch
Scenario
- Start: 7:00 AM
- End: 7:00 PM
- Meal break: 1 hour unpaid
- Rest breaks: Two 15-minute paid breaks
Calculation
- 1. Total time: 7:00 PM – 7:00 AM = 12 hours
- 2. Unpaid breaks: 1 hour
- 3. Paid work hours: 12h – 1h = 11 hours
Example 3: Part-Time Shift with Paid Breaks Only
Scenario
- Start: 4:00 PM
- End: 9:00 PM
- Rest break: 15 minutes paid
- No meal break (shift under 6 hours)
Calculation
- 1. Total time: 9:00 PM – 4:00 PM = 5 hours
- 2. Unpaid breaks: 0
- 3. Paid work hours: 5h – 0 = 5 hours
Example 4: Overnight Shift
Scenario
- Start: 11:00 PM
- End: 7:00 AM (next day)
- Meal break: 30 minutes unpaid
Calculation
- 1. Hours before midnight: 12:00 AM – 11:00 PM = 1 hour
- 2. Hours after midnight: 7:00 AM – 12:00 AM = 7 hours
- 3. Total time: 1h + 7h = 8 hours
- 4. Paid work hours: 8h – 30m = 7h 30m (7.5 hours)
Time Conversion Reference
Use this table to convert minutes to decimal hours for payroll:
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 5 | 0.08 | 35 | 0.58 |
| 10 | 0.17 | 40 | 0.67 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.33 | 50 | 0.83 |
| 30 | 0.50 | 55 | 0.92 |
Common Mistakes to Avoid
- Forgetting to subtract unpaid breaks – Always deduct meal break time from your total
- Subtracting paid breaks – Short rest breaks should NOT reduce your paid hours
- Incorrect overnight calculations – Remember to split the calculation at midnight
- Rounding errors – Use decimal conversion tables for accuracy
- Not tracking break time – Keep records of actual break times taken
Quick Calculator Tool
Skip the math and use our free Break Time Calculator to instantly determine your paid working hours:
Try Our Break Time Calculator
Enter your shift times and breaks to instantly see your total paid working hours. Works for any schedule including overnight shifts.
Open Break Time CalculatorWhen to Use These Calculations
- Verifying your paycheck: Compare calculated hours to what you were paid
- Planning overtime: Know when you'll hit 40 hours for overtime pay
- Scheduling: Plan your day knowing exactly how long you'll be paid
- Time-off requests: Calculate partial day absences accurately
- Freelance/contract work: Track billable vs. non-billable time